Sheet registering device



Feb. 27, 1968 w, w DM 3,370,847

SHEET REGISTERING DEVICE Filed April 30, 1965 I N VENTOR.

WILLIAM H.WEIDMAN 23 BY I .l E: I

ATTORNEYS United States Patent 3,370,847 SHEET REGISTERING DEVICE William H. Weidman, Cleveland, Ohio, assignor to Harris-Intertype Corporation, Cleveland, Ohio, a corporation of Delaware Filed Apr. 39, 1965, Ser. No. 452,175 4 Claims. (Cl. 271-66) This invention relates to a sheet hold-down mechanism for holdin the leading edge of sheets of paper which are fed in an underlapped manner to a sheet handling device, and which is an improvement on the hold-down mechanism described in United States Patent No. 2,984,483, issued to Kist, May 16, 1961, and assigned to the same assigneeas the present application.

When feeding sheets of paper in closely spaced succession to a printing press cylinder or sheet handling machine, it is necessary first to register each sheet before it is gripped by the cylinder. Registration of each sheet is commonly accomplished by placing a stop member on the sheet feed table immediately to the rear of the printing press cylinder, allowing the sheet to settle against the stop member, and then directing the sheet to the cylinder in a timed sequence. In order to capture the leading edge of each sheet so that it can be front registered, overguide hook means are usually employed which guide the leading edge of each sheet against the front stops. After the sheet has registered and the hook and stop means are withdrawn below the table, the sheet is gripped by a feed roll or the like and allowed to pass to the cylinder. The hook means are then raised preparatory to capturing the leading edge of a following sheet.

In raising the hook and front stop means, however, the previously registered sheet is raised above the feed table. There is a tendency for the leading edge of the following sheet to cling to the underneath surface of the previously registered sheet, and therefore it is necessary to insure that the leading edge of the following sheet will be guided under the overguide hook means and thereby front registered.

One method of holding down the leading edge of the following sheet is to provide a suction holding means, as done by Kist, cited above. As each sheet approaches the front register means, the sucker mechanism intercepts the leading edge grasping the sheet by a vacuum. The whole sucker mechanism is then moved forward at the same velocity as the sheet until it is beneath the overhanging portion of the overguide hook. The vacuum on the sucker means is removed and the sucker mechanism reciprocated to a point to the rear of the front registering mechanism to await the arrival of a succeeding sheet. This type of mechanism requires that the application of vacuum to the leading edge of each sheet be carefully timed so that the sheet will not be withdrawn from underneath the overguide hook means. It further requires that the sucker mechanism be accelerated in perfectly timed relation to the speed of the incoming sheet. For effectiveness of the sucker mechanism it is required that each vacuum port, be covered with the sheet of paper so that the vacuum will not be lost.

In the present invention the leading edge of each sheet isheld down against the feed table by a jet of air which passes substantially parallel to and along the surface of the feed table. This jet of air will cause an area of reduced pressure beneath the leading edge of each sheet, thus causing it to be deflected toward the feed plate and underneath the overguide hook means. As each incoming sheet passes the air jet nozzles, which are preferably placed directly behind each overguide hook means, the leading edge will snap down toward the feed plate due 3,370,847 Patented Feb. 27, 1968 to the lowered pressure rather than clinging to the preceding previously registered sheet. The direction of flow of the air jet will also aid in driving the sheet of paper against the front stop mechanism, and since there is a film of air over the feed table, the paper will positively settle against the front register stops.

By using a jet of air rather than a vacuum to hold down each sheet, several other advantages are evident. For example, the hold-down air system would not be subject to plugging due to dirt or lint which might enter the sucker ports, and only a single filter would be required at the input of the air supply. The use of airblast hold-downs allows the placement of the hold-down mechanism closer to the edge of each sheet to provide more positive control over the corners since there is no requirement that each airblast port be covered by the paper, as in the case with sucker type hold-downs which would lose their effectiveness if any ports are left uncovered.

It is a primary object of this invention to provide an improved mechanism for holding down the leading edge of sheets of paper which are fed in a closely spaced, underlapped manner to a sheet handling device, such as a printing press cylinder or the like.

It is another object of this invention to eliminate a considerable number of moving parts which were previously necessary in sucker type hold-down mechanisms.

It is another object of this invention to eliminate the necessity of accurate sheet timing which is employed in the sucker type sheet hold-down mechanisms.

It is a further object of this invention to provide for more positive control of the corners of each sheet of paper in the feed mechanism.

It is another object of this invention to eliminate the necessity for accurate air valve timing for the sheet holding mechanism.

It is an additional object of this invention to eliminate the problem of lint and dirt plugging the hold-down air system.

It is another object of this invention to provide means to' lubricate the incoming sheets of paper by providing a film of air under the leading edge of each sheet.

Other objects and advantages of the invention will be apparent from the following description, the accompanying drawing and the appended claims.

In the drawing:

FIG. 1 is a diagrammatic representation of portions of a printing press showing the operation of this inventlon;

FIG. 2 is a sectional view of the invention taken along the line 22 of FIG. 3, showing the relative positions of the printing press cylinder, the front registering means, the sheet feed rolls, and the airblast hold-down means of this invention;

FIG. 3 is a plan view of a portion of the feed table of a printing press showing the relative positions of the feed rolls, the front registering mechanism and the airblast holdoown means of this invention;

FIG. 4 is an exploded view of one embodiment of the airblast hold-down means; and

FIG. 5 is a sectional View of the printing press feed plate showing another embodiment of the airblast holddown means of this invention mounted therein.

Referring to the drawings, which illustrate preferred embodiments of the invention, and particularly to FIGS. land 2, sheets S1 and S2 from a conventional pile feeder are fed along feed table 10 in an underlapped fashion, that is, the leading edge of each succeeding sheet underlies the tail end of a previous sheet. A feed mechanism, not shown, drives the stream of sheets down the feed table toward the registering mechanism 12 located at the forward end of the feed table. A cylinder 13, which may be an impression cylinder of a printing press or a similar cylinder in a sheet handling device, and which a of the feed table. Positioned above the feed roll 21' is an idler wheel 22, pivoted on shaft 24. The registering mechanism 12, consisting of a stop member 15 and an overguide hook member 15, is positioned on the feed table adjacent the feed rolls to intercept each sheet and provide a means to front register each sheet. Located at the rear of the registering mechanism 12 in an opening 23 in the feed table is an air passageway or nozzle 18.

As sheet S1 advances along the feed table, it will be intercepted underneath the overhanging portion 17 of the overguide hook 16 and be forced against the front registering stop member 15 in a conventional manner. After the sheet has settled against the front stops, the front registering mechanism 12 is withdrawn below the feed table. Idler wheel 22 is then lowered, placing the sheet in contact with the feed roll 21, thus driving the sheet to the cylinder 13 where it will be taken by the conventional mechanism.

As the sheet S1 is being taken by cylinder 13, a second sheet follows. The front stops 15 and overguide hooks 16 of registering mechanism 12 are raised to the position shown in FIG. 1, and in the process, sheet S1 will be lifted above the feed table by the overhanging portion 17 of hook 16 and by stop member 15. Sheet S2 will have a tendency to cling to the underneath surface of sheet S1, as shown by the solid lines in FIG. 1. In.

order to insure that sheet S2 will be intercepted by the front registering mechanism, the overhanging portion 17 of hook 16 is provided with a knife edge which tends to scrape sheet S2 from the underneath surface of sheet S1.

As further insurance that sheet S2 will front register, a flat jet or film of air is passed along the surface of feed table from nozzle 18 causing an area of reduced pressure beneath sheet S2, thus bringing sheet S2 to the position shown by the dotted lines in FIG. 1. This film of air, while causing the sheet S2 to approach the surface of the feed table, also provides lubrication between the sheet and the feed table which aids the settling of the sheet against the front stop member 15. After sheet S2 has been front registered, it may also be side registered in the conventional manner as described in the Kist patent, cited above. Upon completion of front and side registration, the front stops and overguide hooks 16 are again withdrawn below the feed table. Idler wheel 22 is lowered, and the sheet is driven to the printing press cylinder 13 by the feed roll 21. The sequence of operation is thus repeated. The stop member 15, overguide hook 16, and idler wheel 22 are all actuated in a timed sequence which is described in the above cited Kist patent.

Each of the airblast nozzles 18 is located directly behind each front registering mechanism 12 to insure that the leading edge of each following sheet will be caught over the overhanging portion 17 of overguide hooks 16 (FIG. 3). By using airblast hold-downs rather than the suction hold-downs, it is possible to position the holddown means closer to the edge of each sheet, giving more positive control over the corners of each sheet.

One actual embodiment of the airblast hold-down assembly, which has been successfully utilized, is shown in FIG. 4. The hold-down assembly is formed from a and create an area of low pressure causing the sheets to be deflected against the feed table.

The angle which the airblast makes with the feed table will depend on the air pressure used, the size and weight of each sheet, and the total width of the sheets. In one embodiment, using an air pressure in the order of 15 p.s.i. and with the airblast hold-down nozzle located approximately fourinches behind the registering mechanism 12, an angle of about 5 was found useful. For heavier paper, or longer sheets, and higher air pressure supplies, the angle at which the air blast enters the table can be higher, up to approximately 45. For optimum effectiveness of the hold-down effect, the surface of the table in front of the airblast nozzle must be smooth.

The airblast hold-down can also take the form shown in FIG. 5 of an brass tube 35 which has been flattened on its end 36 to give an opening /1" wide by V 2" high. The flattened portion of the tube then is mounted in a recess 37 in the feed table with the top portion of the tube flush with the surface of the table. This particular embodiment would allow the air jet to flow across the feed table toward the registering mechanism at a shallow angle. a

The nozzle assemblies 19 are connected to each other and to a source of air pressure, such as pump 33, through hose 28 and valve member 32. While it is possible to supply the film of air to the feed table continuously, it

is not absolutely necessary. It is required, however, that the air pressure be supplied through the hold-down nozzle prior to the approach of the leading edge of an underlying sheet such that it will be held against the surface of the feed table and front registered as described above. After the sheets are front registered, the air supply can be diverted for other uses by turning valve 32 and (103-.

necting the air supply to line 34.. 7

By using a blast of air to create an area of reduced pressure under each sheet of a series of sheets of paper fed in an underlapped manner to a printing press cylinder, several elements which were necessary in vacuum type hold-down mechanisms have been eliminated, accurate timing of the air supply is no longer necessary since the airblast type hold-down can operate continuwhich is defined in the appended claims.

What. is claimed is: Y

1. Apparatus for feeding sheets in 'an underlapped manner to a sheet handling machine which includes a feed table forming a support for the sheets, registering means to intercept and front register each sheet moved over said table prior to feeding each sheet to said machine, a first member positioned beneath said feed table, a second member positioned on said first member and having a top surface flush with the top of said feed tableand defining with said first member a slot directed at a shallow angle to the feed table, and a passageway in said first member adapted to be connected to a source of air pressure and communicating with the slot defined by the first and second members for creating a jet of air issuing from said slot and moving over the surface of said feed table toward said registering means in the same direction as the sheet movement to create an area of low pressure effective to hold the leading edge of incoming sheets of paper close to the surface of said feed table.

2. The apparatus as defined in claim 1 wherein the slot as defined by the first and second members makes an angle of between 5 and 45 to said feed table.

3. An apparatus for feeding sheets in an underlapped manner to a cylinder in a sheet handling machine which includes a feed table forming a support for the sheets, means movable over a portion of said table to hook the leading edge of one sheet moved over said table while it is beneath a portion of a preceding sheet, stop means to front register each sheet after it has been hooked, and means to guide the leading edge of each sheet so that it can be hooked while the preceding sheet is being taken off said table including a plurality of air jet means each arranged directly behind a corresponding hook means to direct a fiat jet of air moving over the surface of said feed table and toward said hook and stop means in the same direction as the sheet movement to create an area of reduced pressure beneath the leading edge of each sheet and below the level of said hook means as it approaches the hook means to insure that that sheet will be intercepted by said hook means.

4. An apparatus for feeding a stream of sheets in an underlapped manner to a sheet handling machine which includes a feed table forming a support for the sheets, a series of feed rolls positioned in said feed table adapted to advance each sheet to said sheet handling machine, a series of stop members positioned in said feed table adapted to front register each sheet of said underlapped stream of sheets, a series of overguide hook members positioned in said feed table in the vicinity of said stop members adapted to intercept each sheet of said stream prior to front registration of each sheet, and a series of nozzles each arranged in said feed table directly behind a corresponding overguide hook and each constructed to direct a jet of air close to over said feed table against a corresponding overguide hook in the same direction as the sheet movement to create an area of reduced pressure beneath the leading edge of each sheet as it approaches said overguide hooks whereby the leading edge of each sheet of paper may be held close to the surface of said feed table and directed under said overguide hooks while a preceding, overlaid, previously registered sheet is being fed to said sheet handling machine.

References Cited UNITED STATES PATENTS 2,984,483 5/1961 Kist 27158 3,126,200 3/1964 Rehm 27126 3,168,307 2/1965 Walton et a1 271-26 3,268,222 8/1966 Off 226196 FOREIGN PATENTS 184,884 9/1963 Sweden.

7 ROBERT B. REEVES, Primary Examiner.

M. HENSON WOOD, IR., Examiner.

J. N. ERLICH, R. A. SCHACHER, Assistant Examiners. 

1. APPARATUS FOR FEEDING SHEETS IN AN UNDERLAPPED MANNER TO A SHEET HANDLING MACHINE WHICH INCLUDES A FEED TABLE FORMING A SUPPORT FOR THE SHEETS, REGISTERING MEANS TO INTERCEPT AND FRONT REGISTER EACH SHEET MOVED OVER SAID TABLE PRIOR TO FEEDING EACH SHEET TO SAID MACHINE, A FIRST MEMBER POSITIONED BENEATH SAID FEED TABLE, A SECOND MEMBER POSITIONED ON SAID FIRST MEMBER AND HAVING A TOP SURFACE FLUSH WITH THE TOP OF SAID FEED TABLE AND DEFINING WITH SAID FIRST MEMBER A SLOT DIRECTED AT A SHALLOW ANGLE TO THE FEED TABLE, AND A PASSAGEWAY IN SAID FIRST MEMBER ADAPTED TO BE CONNECTED TO A SOURCE OF AIR PRESSURE AND COMMUNICATING WITH THE SLOT DEFINED BY THE FIRST AND SECOND MEMBERS FOR CREATING A JET OF AIR ISSUING FROM SAID SLOT AND MOVING OVER THE SURFACE OF SAID FREE TABLE TOWARD SAID REGISTERING MEANS IN THE SAME DIRECTION AS THE SHEET MOVEMENT TO CREATE AN AREA OF LOW PRESSURE EFFECTIVE TO HOLD THE LEADING EDGE OF INCOMING SHEETS OF PAPER CLOSE TO THE SURFACE OF SAID FEED TABLE. 